AIM: To evaluate the therapeutic efficacy, safety and tolerability of newly developed preservative-free (PF) latanoprost generic [TJO-002] and compare it with benzalkonium chloride (BAK)-preserved latanoprost [Xalatan®] in patients with primary open angle glaucoma (POAG) and ocular hypertension (OHT). METHODS: Included patients were aged ≥19y with POAG/OHT. After a washout period, patients with IOP 21-35 mm Hg at 9 a.m. were enrolled. After a full ophthalmic and glaucoma examination, 144 patients with POAG and OHT participated in this study. Subjects were randomly assigned either PF latanoprost (74 eyes) or BAK-preserved latanoprost (70 eyes). All subjects were examined at 4, 8, and 12wk after first administration. At each follow-up visit, IOP was measured at 9 a.m. and 5 p.m. and compliance was assessed. Throughout the study, all adverse events were recorded and monitored by the masked investigators who measured IOP. RESULTS: Both groups showed a statistically significant decrease of average diurnal IOP at 12wk compared to baseline (-7.21±3.10 mm Hg in the PF latanoprost group and -7.02±3.17 mm Hg in the BAK latanoprost group, both P<0.0001). There was no statistically significant diurnal IOP variation between the groups. In terms of tolerability, pruritus, burning/stinging, and sticky eye sensation, severity was significantly lower in the PF latanoprost group than in the BAK latanoprost group (P<0.05). CONCLUSION: PF latanoprost has at least similar efficacy in terms of IOP reduction and better tolerability compared with BAK latanoprost.